I just got one at my local Costco, it even came with a USB wall charger. I am not sure if I am able to plug my S9 straight into the wall charger. It is a standard female USB 5V 500mah (at least that's what is says for the output).
Any ways, for who ever has one of these, how do you like it for the S9. I think it'd mostly good if I decide to play flash games or few movies for a road trip.